α1 adrenergic receptors (hereinafter to be abbreviated as an α1 receptor) are widely distributed in the cardiovascular system, lower urinary tracts and the like, and involved in sympathetic nerve response activities. Since the relationship with pathologies such as hypertension, cardiac hypertrophy and dysuria has been suggested, α1 receptors have attracted attention for some time, and many attempts have been made to develop therapeutic drugs. In recent years, it has been clarified that α1 blockers are effective for dysuria associated with benign prostatic hypertrophy (BPH). Coupled with the marketability thereof, extensive interests have been created again (non-patent document 1).
The α1 receptor gene was cloned from the late 1980s to the early 1990s, and the presence of three subtypes of α1A, α1B and α1D has been clarified. Among these, α1D receptor has been confirmed to express in a number of tissues such as blood vessel, brain, spinal cord, gastrointestinal tract, bladder, kidney and the like. While the physiological function of α1D receptor has not been elucidated, α1D receptor antagonists may provide therapeutic drugs for various diseases since they are localized widely.
A greater distribution of α1D receptors in the bladder, parasympathetic nerve nucleus of the sacral cord, and the like as compared to other subtypes has been confirmed (non-patent documents 2, 3), thus suggesting strong involvement in urine storage. In fact, there is a report on a significant increase in the bladder capacity and the single voided volume in α1D knockout mouse (non-patent document 4). Recent reports have documented that the expression amount of α1D receptor mRNA increases in the bladder of BPH patients and BPH model animal (non-patent documents 5 and 6), the bladder muscle isolated from BPH patients may show a promoted contractile function via α1D receptor (non-patent document 7) and the like, thus suggesting a possible involvement of an α1D receptor expressed in the bladder in the pathology of BPH. From the foregoing, an α1D receptor antagonist is promising as an agent for the prophylaxis or treatment of a lower urinary tract disease and the like.
As examples of the compound showing a selective α1D receptor antagonistic action, non-patent document 8 describes a compound represented by the formula
patent document 1 describes a compound represented by the formula
patent document 2 describes a compound represented by the formula
patent document 3 describes a compound represented by the formula
and non-patent document 9 describes a compound represented by the formula

In addition, as iminopyridine derivatives, those described in patent documents 4-7 and non-patent documents 10-32 are known.    patent document 1: WO00/04012    patent document 2: U.S. Pat. No. 3,997,666    patent document 3: WO00/04027    patent document 4: DD 263759    patent document 5: EP47977    patent document 6: DD106377    patent document 7: JP-B-48-40544    non-patent document 1: Yakugaku Zasshi 126, 187-198, 2006    non-patent document 2: Molecular Brain Research 63, 254-261, 1999    non-patent document 3: J. Urol. 160: 937-943., 1998    non-patent document 4: J. Urol. 174: 370-4., 2005    non-patent document 5: J. Urol. 170: 649-653., 2003    non-patent document 6: J. Urol. 167: 1513-1521., 2002    non-patent document 7: J. Urol. 173: 657-61., 2005    non-patent document 8: Eur. J. Pharmacol., 272, (1995), R5-R6    non-patent document 9: Eur. J. Pharmacol., 445, (2002), 21-29    non-patent document 10: Heteroatom Chemistry (2004), 15(4), 293-299    non-patent document 11: Latvijas Kimijas Zurnals (1995), (3-4), 109-113    non-patent document 12: Arzneimittel-Forschung (1995), 45(9), 957-62    non-patent document 13: Journal of the Chinese Chemical Society (Taipei, Taiwan) (1993), 40(2), 181-7    non-patent document 14: Zhurnal Strukturnoi Khimii (1988), 29(5), 169-72    non-patent document 15: Latvijas PSR Zinatnu Akademijas Vestis, Kimijas Serija (1986), (4), 471-8    non-patent document 16: Latvijas PSR Zinatnu Akademijas Vestis, Kimijas Serija (1985), (3), 351-8    non-patent document 17: Latvijas PSR Zinatnu Akademijas Vestis, Kimijas Serija (1985), (2), 200-5    non-patent document 18: Tetrahedron (1980), 36(6), 785-9    non-patent document 19: Zeitschrift fuer Naturforschung, Teil B: Anorganische Chemie, Organische Chemie (1980), 35B(4), 490-3    non-patent document 20: Tetrahedron (1979), 35(21), 2591-3    non-patent document 21: Fette, Seifen, Anstrichmittel (1980), 82(2), 82-6    non-patent document 22: Tetrahedron (1979), 35(6), 809-12    non-patent document 23: Journal of Chemical Society of Japan (1978), (5), 730-6    non-patent document 24: Tetrahedron Letters (1977), (15), 1333-6    non-patent document 25: Journal fuer Praktische Chemie (Leipzig) (1976), 318(5), 705-30    non-patent document 26: Zeitschrift fuer Chemie (1973), 13(9), 342-3    non-patent document 27: Journal of Chemical Society [Section] C: Organic (1971), (10), 1892-5    non-patent document 28: Angewandte Chemie, International Edition in English (1971), 10(1), 68-70    non-patent document 29: Chemical & Pharmaceutical Bulletin (1969), 17(11), 2209-16    non-patent document 30: Chemical & Pharmaceutical Bulletin (1966), 14(8), 861-6    non-patent document 31: Doklady Akademii Nauk SSSR (1949), 66, 647-50    non-patent document 32: Ann. (1925), 443, 272-309